Device for truing grinding wheels



Nov. 18, 1952 o. M. r-:LlAssoN ETAL DEVICE FOR TRUING GRINDING WHEELS 2 "SHEETS- SHEET 1 Filed March 18, 1950 INVENTORS m n @d m ./J m /EmN//A 2 Z JZ wd Nov. 18, 1952 o. M. ELlAssoN ET AL DEVICE FOR TRUING GRINDING WHEELS 2 SHEETS--SHEET 2 Filed March 18, 1950 nl nl INVENTORS ATTORNEY Patented Nov. 18, 1952 DEVICE FOR TRUINGv GRINDING WHEELS Olof Manfred Eliasson and John Adolf Njd,

Sodertalje, Sweden, assignors to Maskinaktiebolaget Karlebo, Stockholm, Sweden, a corporation'of Sweden Appiication March 18, 1950, Serial No. 150,364 In Sweden March 23, 1949 6 Claims.

This invention relates to a device for truing grinding wheels adapted for work in prole and copying grinding machines.

The invention has for its object to provide means for truing a grinding wheel to the same shape as that of a feeler whereby the grinding wheel` may have an arbitrary proiile e. g. a cylindrical one, at the grinding of work-pieces to an exact copy of a template.

A further object of the invention is to provide an apparatus for truing the grinding wheel to the same shape as that of the ,feeler in a simple and accurate manner.

The invention is described in detail in the iollowing description, with reference to the accompanying drawings, wherein Fig. l shows a horizontal view oi the device mounted on a copying grinding machine, Fig. 2 shows a detail view of an adjusting means, Fig. 3 shows a partly sectioned View of the device, Fig. 4 shows a view of a holder for a truing means and its connection to the work table from the left in Fig. 3, Fig. 5 is an enlarged sectional View of the holder and the connection as viewed in Fig. l and Fig. 6 shows a view of an adjusting template for the truing means.

In Fig. 1 is I a table on which various templates I are attachable in a suitable manner. An exchangeable feeler 2 is movable over the table I in all directions in a plane parallel to the table I and attached to va pantograph 3 of known construction. The pantograph is in a known manner connected with a work table fl for displacing the same with movements which exactly copy the movements of the feeler with a predetermined ratio, e, g. 1:5. In order that a proiile or copying grinding machine of known type may work with the greatest possible precision, the feeler has the shape of a point so that the smallest possible contact surface will touch the template. In consequence the grinding wheel must have a small contact surface against the work piece, with the result that its thin edge is rapidly worn down and the precision of the grinding is hazarded.

According to the present invention the grinding wheel is given a shape corresponding exactly to the shape of the feeler and this shape need not be pointed but the working surface of the grinding wheel may be larger whereby the time between the truing operations of the grinding wheel is increased and the precision will be maintained longer. One object of the invention is, by means of a special apparatus, to produce the shape of ther feeler on the working surface of the grinding` wheel.

A grinding wheell 5 is provided in a stock 6 which, on the one hand, is pivotable about an axis parallel to the edge li of the work table l and, on the other hand, about a stud 45 journalled in the base 4I of the machine perpendicularly to the axis of the grinding wheel 5. During grinding the stock 6 performs a reciprocating movement perpendicularly to or at an angle to the plane of the work table 4 on a slideway 'i connected to the frame of the machine. A link system 8 is connected to the slideway 1 and is pivotable in the adjusting plane of the stock 6, that is at right angles to its pivot axis 8' connected to the slideway 1. A support 9 for a truing means I0 is joined with the link system 8 and with the work table 4 through a pivotable slide I'I and a dog arm I 2 so that the support will perform the same movements as the work table 4 and the support is also connected to an adjustable guide member I3 on the table I by means of a telescopic shaft I4 and universal joints I5.

The guide member I3 is adjustable along a slideway I6 of the table I in order to be placeable in a suitable position so that the guide member I3 may remain in a fixed position between truing operations` and will not impede the feeler 2 in its'movements along the contour of the template I Aduring grinding operations. The guide member I3 Yhas attached to it a semicylindrical turnable pin I8 in which one half of the cylinder is cut away to form a plane guiding face I7, see also Fig. 3, extending exactly along the axis of rotation of said pin I8 through its axis of rotation. The pin I8 is elongated upwards by a shaft I9 on which a conical pinion 2Q is fixed which engages a conical gear 2| at right angles thereto connected with the telescopic shaft It. The guiding face ll' is adjustable by means of argrip 22 manually operable and connected with the shaft I9.

The pivoting device of the support@ is similar to the guide member i3. The revolving movements of the telescopic shaft I4 are transmitted through a conical gear 23, 24 to a shaft 25 to which a rotatably mounted holder 26 for the truing means I D is iixed. Said truing means I0, which usually is a diamond, is attached to the holder 26 in such a manner that the point of the truing means will lie on the axis of rotation of the holder 26. For that reason a template 27, Fig. 6, is used having such dimensions that the point of the truing means when contacting the template 27, which is placed against the side of the grinding wheel 5, is automatically adjusted in the right position.

The gears 20, 2| and 23, 24 have a gearing ratio of 1:1 and the truing means I0 is therefore pivoted with the same angle deviation as the guiding face I'I when being rotated.

The link system 8 consisting of one or more links is movable on stud bearings 2S which permit pivoting of the link system only in one plane at right angles to the longitudinal direction of the slideway I thereby permitting the support 9 to be swung aside away from the grinding wheel and to be held in this position by means of a snap spring 29. Before the support can be swung, the slide II which is pivotable about a detachable stud bearing must be loosened from the dog arm I2 which thereafter is pushed out of a dovetailed groove 3l after the clamping screws 32 have been loosened. The position of the dog arm I2 is determined by adjustable bolts 33 (Fig. 2) which are fixed in their positions by means of clamping bolts 34 and in right position of the dog arm I2 are engaging a shoulder 35 on the table 4.

The connection between the support 9 and the slide I I is not rigid but the support is displaceable in guides 36 (Fig. 5) and will automatically be adjusted in the longitudinal direction of the slide l I according to the angle between the slideway 'l' and the work table 4. As the slideway I with the stock 6 is also pivotable on a stud 4D journalled in the base 4I of the machine perpendicularly to the axis of the grinding wheel 5, the slide II has a corresponding possibility of swinging about a stud 31 whereby the support 9 will always follow the movements of the slideway I in spite of the dog arm I2 being stationary relatively to the work table 4.

In truing a grinding wheel, the template I is not used and the device is operated in the following manner. The feeler 2 having a suitable shape for the work is provided at the arm 3 of the pantograph, and ya grinding wheel having a somewhat similar shape as the feeler and a width corresponding approximately to the ratio of the pantograph, e. g. V5 of the width of the feeler, is mounted in the stock 6. The holder I3 is attached at a suitable place to the table I so as not to interfere with a template I on the table whereupon one edge of the feeler 2, e. g. the beveled side (right side) thereof as seen in Fig. 1, is brought into contact with the guiding face I'I which is turned into such positions that the contact between the feeler 2 and the guiding face I'I always takes place in the axis of rotation of the guiding face. The dog arm I2 is then adjusted by means of the clamping bolts 33 so that the truing means I0 just contacts the left side of the grinding wheel 5. In the course of the operation it is only necessary to see that the feeler 2 is moved along the guiding face I'I in such a manner that the contacting face always extends through the axis of rotation of the guiding face which is Drought about by simultaneous rotation of the grip 22 and displacement of the feeler 2. It is especially important that corner points of the feeler exactly pass through the center of the guiding face. When the feeler has been moved around the axis of rotation of the guiding face, the truing means, due to the movement of the pantograph and the rotation of the guiding face, has been displaced around the edge of the grinding Wheel 5 by the table 4 and the prole of the feeler has been copied on the grinding wheel in a reduced scale.

It can never be questioned that the truing means will cut too deep into the grinding wheel for as soon as the feeler is out of contact with the guiding face, the truing means is displaced away from the grinding wheel. When the truing operation is over, the support 9 is swung away in the manner described above and is then ready for renewed operation after forward swinging since the device is already adjusted in its right working position. Retruing can consequently be carried out very rapidly and carefully.

In certain cases tools are to be provided with clearance at some side surface and the profile of the grinding wheel must then be corrected. This is achievable with the device without any changes whatever. The slideway 'I is pivoted around the axis parallel to the edge 4 of the work table or the stock 6 is pivoted around the axis perpendicular thereto. The movements of the support 9 and the truing means IIJ follow the movements of the tracing pin and the guiding face respectively under all circumstances and the prole of the grinding wheel is always, in a plane parallel to the work table 4, the same as the prole of the tracing pin.

Details of the device can of course be carried out in various manners but the characteristic features of the device over hitherto known constructions are to be seen from the description.

What we claim is:

1. A grinding machine comprising, in combination, a base, a grinding wheel support mounted on the base, a grinding wheel rotatably mounted on said support, a work table mounted on the base for movement in all directions in a horizontal plane, truing means for the grinding wheel, said truing means having a working point and being rotatably connected with said work table, a templet table mounted on the base, a guide pin rotatably mounted on the templet table and having a guide face passing through the axis of the guide pin, means connecting the guide pin with the truing means for transmitting the rotational movement of the guide pin to the truing means, a pantograph mechanism having one end connected to the work table for effecting movement thereof in all directions in the horizontal plane, and a feeler connected to the other end of said pantograph mechanism, said feeler being adapted to engage and follow the said guide face of the guide pin, whereby to cause said working point of the truing means to be moved in a path corresponding to the shape of the feeler to impart a corresponding shape to the grinding wheel.

2. A grinding machine as set forth in claim 1, wherein said connecting means between said guide pin and said truing means consists of positively working means.

3. A grinding machine as dened in claim l, wherein the connecting means between said guide pin and said truing means comprises gears, universal joints and a telescopic shaft, the ratio of the gears being 1:1.

4. A grinding machine as defined in claim l, wherein said truing means is secured to a slide 5 adjustable in a direction at right angles to the axis of said grinding Wheel.

5. A grinding machine as defined in claim 1 wherein said truing means is secured to a slide adjustable in a direction at right angles to the 6 REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,960,760 Sutton May 29, 1934 2,038,455 Studer Apr. 21, 1936 2,171,211 Day Aug. 29, 1939 2,347,283 Ross Apr. 25, 1944 2,351,159 Stewart June 13, 1944 2,452,509 Victory Oct. 26, 1948 2,469,844 Porter May 10, 1949 

